Spring-程序中获取注册bean的方式

获得spring里注册Bean的四种方法，特别是第三种方法，简单： 
一：方法一（多在struts框架中）继承BaseDispatchAction 

import com.mas.wawacommunity.wap.service.UserManager; 

public class BaseDispatchAction extends DispatchAction {
　　/**
　　 * web应用上下文环境变量
　　 */
　　protected WebApplicationContext ctx; 

　　protected UserManager userMgr; 

　　/**
　　 * 获得注册Bean
　　 * @param beanName String 注册Bean的名称
　　 * @return
　　 */
　　protected final Object getBean(String beanName) {
　　　　return ctx.getBean(beanName);
　　} 

　　protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
　　　　javax.servlet.http.HttpServletRequest request,
　　　　javax.servlet.http.HttpServletResponse response) {
　　　　return mapping.findForward("index");
　　} 

　　public void setServlet(ActionServlet servlet) {
　　　　this.servlet = servlet;
　　　　this.ctx = WebApplicationContextUtils.getWebApplicationContext(servlet.getServletContext());
　　　　this.userMgr = (UserManager) getBean("userManager");
　　} 
} 

二：方法二实现BeanFactoryAware 
一定要在spring.xml中加上:

<bean id="serviceLocator" class="com.am.oa.commons.service.ServiceLocator" singleton="true" /> 

当对serviceLocator实例时就自动设置BeanFactory,以便后来可直接用beanFactory

public class ServiceLocator implements BeanFactoryAware {
　　private static BeanFactory beanFactory = null; 

　　private static ServiceLocator servlocator = null; 

　　public void setBeanFactory(BeanFactory factory) throws BeansException {
　　　　this.beanFactory = factory;
　　} 

　　public BeanFactory getBeanFactory() {
　　　　return beanFactory;
　　} 

　　public static ServiceLocator getInstance() {
　　　　if (servlocator == null)
　　　　　　servlocator = (ServiceLocator) beanFactory.getBean("serviceLocator");
　　　　return servlocator;
　　} 

　　/**
　　* 根据提供的bean名称得到相应的服务类
　　* @param servName bean名称
　　*/
　　public static Object getService(String servName) {
　　　　return beanFactory.getBean(servName);
　　} 

　　/**
　　* 根据提供的bean名称得到对应于指定类型的服务类
　　* @param servName bean名称
　　* @param clazz 返回的bean类型,若类型不匹配,将抛出异常
　　*/
　　public static Object getService(String servName, Class clazz) {
　　　　return beanFactory.getBean(servName, clazz);
　　}
} 

action调用: 

public class UserAction extends BaseAction implements Action,ModelDriven{ 

private Users user = new Users();
protected ServiceLocator service = ServiceLocator.getInstance();
UserService userService = (UserService)service.getService("userService"); 

public String execute() throws Exception {
return SUCCESS;
} 

public Object getModel() {
return user;
} 

public String getAllUser(){
HttpServletRequest request = ServletActionContext.getRequest();
List ls=userService.LoadAllObject( Users.class );
request.setAttribute("user",ls);
this.setUrl("/yonghu.jsp");
return SUCCESS;
}
} 

三：方法三实现ApplicationContextAware 
一定要在spring.xml中加上:

<bean id="SpringContextUtil " class="com.am.oa.commons.service.SpringContextUtil " singleton="true" /> 

当对SpringContextUtil 实例时就自动设置applicationContext,以便后来可直接用applicationContext

public class SpringContextUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext; //Spring应用上下文环境 

/**
* 实现ApplicationContextAware接口的回调方法，设置上下文环境
* @param applicationContext
* @throws BeansException
*/
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
　　SpringContextUtil.applicationContext = applicationContext;
} 

/**
* @return ApplicationContext
*/
public static ApplicationContext getApplicationContext() {
return applicationContext;
} 

/**
* 获取对象
* @param name
* @return Object 一个以所给名字注册的bean的实例
* @throws BeansException
*/
public static Object getBean(String name) throws BeansException {
return applicationContext.getBean(name);
} 

/**
* 获取类型为requiredType的对象
* 如果bean不能被类型转换，相应的异常将会被抛出（BeanNotOfRequiredTypeException）
* @param name bean注册名
* @param requiredType 返回对象类型
* @return Object 返回requiredType类型对象
* @throws BeansException
*/
public static Object getBean(String name, Class requiredType) throws BeansException {
return applicationContext.getBean(name, requiredType);
} 

/**
* 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
* @param name
* @return boolean
*/
public static boolean containsBean(String name) {
return applicationContext.containsBean(name);
} 

/**
* 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
* 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
* @param name
* @return boolean
* @throws NoSuchBeanDefinitionException
*/
public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
return applicationContext.isSingleton(name);
} 

/**
* @param name
* @return Class 注册对象的类型
* @throws NoSuchBeanDefinitionException
*/
public static Class getType(String name) throws NoSuchBeanDefinitionException {
return applicationContext.getType(name);
} 

/**
* 如果给定的bean名字在bean定义中有别名，则返回这些别名
* @param name
* @return
* @throws NoSuchBeanDefinitionException
*/
public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
return applicationContext.getAliases(name);
}
} 

action调用：

package com.anymusic.oa.webwork; 

import java.util.List;
import java.util.Map; 

import javax.servlet.http.HttpServletRequest; 

import com.anymusic.oa.commons.service.ServiceLocator;
import com.anymusic.oa.hibernate.pojo.Role;
import com.anymusic.oa.hibernate.pojo.Users;
import com.anymusic.oa.spring.IUserService;
import com.opensymphony.webwork.ServletActionContext;
import com.opensymphony.xwork.Action;
import com.opensymphony.xwork.ActionContext;
import com.opensymphony.xwork.ModelDriven; 

public class UserAction extends BaseAction implements Action,ModelDriven{ 

private Users user = new Users();
//不用再加载springContext.xml文件,因为在web.xml中配置了,在程序中启动是就有了.
UserService userService = (UserService) SpringContextUtil.getBean("userService"); 

public String execute() throws Exception {
return SUCCESS;
} 

public Object getModel() {
return user;
} 

public String getAllUser(){
HttpServletRequest request = ServletActionContext.getRequest();
List ls=userService.LoadAllObject( Users.class );
request.setAttribute("user",ls);
this.setUrl("/yonghu.jsp");
return SUCCESS;
}
} 

四.通过servlet 或listener设置spring的ApplicationContext,以便后来引用. 
注意分别extends ContextLoaderListener和ContextLoaderServlet .

然后就可用SpringContext来getBean. 覆盖原来在web.xml中配置的listener或servlet.

public class SpringContext {
private static ApplicationContext applicationContext; //Spring应用上下文环境 

*/
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
SpringContextUtil.applicationContext = applicationContext;
} 

/**
* @return ApplicationContext
*/
public static ApplicationContext getApplicationContext() {
return applicationContext;
} 

*/
public static Object getBean(String name) throws BeansException {
return applicationContext.getBean(name);
}
}
public class SpringContextLoaderListener extends ContextLoaderListener{ //
public void contextInitialized(ServletContextEvent event) {
super.contextInitialized(event);
SpringContext.setApplicationContext(
WebApplicationContextUtils.getWebApplicationContext(event.getServletContext())
);
}
}
public class SpringContextLoaderServlet extends ContextLoaderServlet {
private ContextLoader contextLoader;
public void init() throws ServletException {
this.contextLoader = createContextLoader();
SpringContext.setApplicationContext(this.contextLoader.initWebApplicationContext(getServletContext()));
}
}